1998 GMC Savana Van Owner's Manual - Page 206

If you have a diesel engine vehicle with two batteries (or more) you should know before you begin that, especially in cold weather, you may not be able to get enough power from a single battery in another vehicle to start yourdiesel engine. NOTICE: If your vehicle hasmore than one battery, use the warranty. of battery that is under the hood the vehicle - this will reduce theelectrical resistance. 2. Get the vehicles close enough so the jumper cables can reach, but besure the vehicles aren't touching each other. If they are, it could cause a ground connection you don't want. You wouldn't be able to start your vehicle, and the bad grounding could damage the electrical systems. To avoid the possibility of the vehicles rolling, set the parking brake firmly on both vehicles involvedin the jump start procedure. Put your automatic transmission in PARK (P). If you leave your radio on, could be badly it damaged. The repairs would not be covered by your 1 -1 4. Open the hoods and locate the batteries. Find the positive (+) and negative (-) terminals on each battery. An electric fan can start even when the engme up is not running and can injure you. Keep hands, clothing and tools away from any underhood electric fan. 3. Turn off the ignition on both vehicles. Turn off all lamps that aren't needed, and radios. This will avoid sparks and help save both batteries, and could save your radio. 5-4